The only Chrome extension that reads Kindle Cloud Reader books aloud. No other TTS tool works on Kindle — Speechify, NaturalReader, and Read Aloud all fail. CastReader uses OCR to extract text from Kindle's encrypted font rendering, something no other extension can do.
Every TTS extension fails on Kindle Cloud Reader because Amazon encrypts text into custom font glyphs rendered as images. CastReader is the only tool that solves this:
- Intercepts Kindle's render pipeline to capture layout data
- Runs tesseract-wasm OCR to extract text with word-level bounding boxes
- Generates natural speech with Kokoro TTS engine
- Syncs word-level highlight to audio playback in real time
This same approach works on WeRead (微信读书), which renders text on Canvas — another platform where every other TTS tool fails.
- Works on every Kindle book in Kindle Cloud Reader (read.amazon.com)
- OCR-based extraction bypasses Amazon's font encryption
- Word-level highlight synced to audio
- Automatic page turning
- One tap to send an entire Kindle or WeRead book to your phone
- Listen as an audiobook — no Audible subscription needed
- Works via Telegram — no extra app required
- Auto-turns pages and syncs chapters in real time
- 15+ site-specific extractors: Notion, Google Docs, arXiv, Medium, Substack, ChatGPT, Claude, Gemini, and more
- Universal extraction: Readability-based algorithm works on any webpage
- Paragraph highlighting: Real-time visual tracking as you listen
- Smart content detection: Skips navigation, ads, and boilerplate
- 40+ languages with automatic detection
- No signup, no account, no subscription
- No usage limits — read as much as you want
- No data collection — all processing happens locally
| Browser | Link |
|---|---|
| Chrome | Chrome Web Store |
| Edge | Edge Add-ons |
| Firefox | Firefox Add-ons |
You open a Kindle book in your browser
→ CastReader extracts text (OCR for Kindle, DOM for regular pages)
→ Kokoro TTS generates natural speech
→ Audio plays with real-time paragraph + word highlighting
→ "Send to Phone" syncs the entire book to your phone as an audiobook
| Platform | Method | Status |
|---|---|---|
| Kindle Cloud Reader | tesseract-wasm OCR + render interception | ✅ Full support |
| WeRead (微信读书) | Canvas text extraction via fetch interception | ✅ Full support |
| Notion | DOM extraction | ✅ |
| Google Docs | DOM extraction | ✅ |
| arXiv | DOM extraction | ✅ |
| Medium / Substack | DOM extraction | ✅ |
| ChatGPT / Claude / Gemini | DOM extraction | ✅ |
| Any webpage | Readability + heuristic extraction | ✅ |
Why don't other TTS extensions work on Kindle? Amazon renders Kindle text using encrypted custom fonts — the actual characters in the DOM are scrambled. Standard DOM-based text extraction gets gibberish. CastReader uses OCR on the rendered page images to get the real text.
Is this legal? CastReader is an accessibility tool. It reads aloud content you've already purchased, similar to your phone's built-in screen reader. No content is downloaded or redistributed.
How does Send to Phone work? Click "Send to Phone" in the extension popup. CastReader syncs the book chapter by chapter to a web player accessible on your phone. It auto-turns pages on desktop and streams content in real time.
Do I need Audible? No. CastReader generates speech from the text of books you already own in your Kindle library. No Audible subscription needed.
Is it really free? Yes. No freemium tier, no monthly limits, no account required. CastReader uses the open-source Kokoro TTS engine which runs on our server at no per-request cost.
- Website
- Listen to Kindle — How Kindle TTS works
- Send to Phone — Desktop to phone audiobook streaming
- Blog — Guides and tutorials
MIT